Title: Sports-related sub concussive impacts in children: MRI & biomechanical correlates Football head injuries involve significant forces and can result in mild to severe traumatic brain injuries. While this has received increasing attention at the professional and collegiate levels, there is little data at the high school level and scarceif any data available for participants in the youth leagues (8-12 years old). This study will relate information about biomechanical forces experienced during a hit in youth football to neurocognitive and imaging data to determine the effects of subconcussive impacts. All elements of this study focus on the objective to increase understanding of pediatric mild Traumatic Brain Injury (mTBI). In this R03 we will investigate the biomechanical and cognitive correlates of diffusion MRI scalar measures of mTBI in children. This project leverages the investments by Wake Forest University Health Sciences which has identified, instrumented and enrolled youth football players, and funded the data collection as part of our ongoing work in this area of critical public importance. We already have acquired a very rich data set of ~30 youth players (8- 12 years old) followed over the course of an entire season (2012 football season). All players were instrumented with the Head Impact Telemetry System (HITS) for collection of real-time impact data during all practices and games. Baseline, post-season and post-concussion multimodal magnetic resonance imaging (MRI), including structural T1-weighted, and diffusion tensor and kurtosis imaging (DTI/DKI) were performed in all subjects. Neurocognitive assessments using the pediatric Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) were obtained at baseline, post-injury, and post-season. Data acquisition is now continuing into the 2013 season with 30 new players already being monitored with HITs, and having all received baseline imaging and neuropsychologic testing including IMPACT testing and additional NIH toolbox measures. We have also recently been awarded internal institutional funding for acquiring a non-contact sport control data set (25 participants), including imaging and cognitive testing at baseline and post-season. This R03 will help fund a graduate student in Biomedical Engineering to assist in the MRI diffusion analyses of the acquired youth football and control data. The utilization of state-of-the-art HITs technology and the acquisition of HITs data at all practices and games provides an extremely thorough characterization of the biomechanical forces experienced by the brains of the young athletes. This unique data set represents the largest of its type in the world, combining imaging, cognitive testing and biomechanical measures in the youth age group. The long term benefit of the research will be to allow equipment designers, researchers, and clinicians to better prevent, mitigate, identify and treat injuries to help make football a safer activity for millions of children.